Screw-driver

ABSTRACT

A screw-driver designed for operation to exert maximum force on the screw being turned, by providing a gripping member on the shank for engagement by the fingers of the hand of the operator to forcibly press the bit of the tool into engagement with the head of the screw. This force, in an axial direction, supplements the force exerted by the other hand in the same direction, as the tool handle is held by the latter for rotating the screw-driver.

United States Patent [191 Bradbury SCREW-DRIVER [76] Inventor: James J.Bradbury, 413 University Bl d-.2 qleb2 9tlill99lsw [22] Filed: May 24,1973 [21] Appl. No.: 363,636

[52] US. Cl 145/50 R [51] Int. Cl B25b 15/00 [58] Field of Search 145/50R [56] References Cited UNITED STATES PATENTS 1,816,359 7/1931 Carlin145/50 R 2,734,413 2/1956 Dunkelberger 145/50 R 2,884,972 5/1959 Harris145/50 R FOREIGN PATENTS OR APPLICATIONS Great Britain 145/50 R m13,812,894 [451 May28, 1974 Primary ExaminerAl Lawrence Smith AssistantExaminer-J. T. Zatarga Attorney, Agent, or FirmSamuel Lebowitz 5 7ABSTRACT A screw-driver designed for operation to exert maximum force onthe screw being turned, by providing a gripping member on the shank forengagement by the fingers of the hand of the operator to forcibly pressthe bit of the tool into engagement with the head of the screw. Thisforce, in an axial direction, supplements the force exerted by the otherhand in the same direction, as the tool handle is held by the latter forrotating the screw-driver.

1 Claim, 3 Drawing Figures SCREW-DRIVER This invention relates to ascrew-driving tool and more particularly to a screw-driver designed foroperation with both hands in order to exert maximum force between thetool and a screw to be rotated thereby.

It is the object of the present invention to provide a rugged andimproved screw-driver which is capable of performing its functionsrapidly and reliably.

The improved screw-driver is provided with a thumb and finger grip onthe shank of the tool which permits the fingers of one hand to guide thetool and press the same against the head of the screw being turned, insupplement to the force exerted by the other hand applied to the handleof the tool in a conventional manner to rotate the screw-driver andforce it against the screwhead.

Other objects and purposes will appear from the detailed description ofthe invention following hereinafter, taken in conjunction with theaccompanying drawing, wherein FIG. 1 is a front elevation of the tool inaccordance with the invention;

FIG. 2 is a vertical sectional view along line 2-2 of FIG. 1; and

FIG. 3 is a perspective view of the tool in the course of its engagementwith a screw when the parts are in the position shown in solid lines inFIG. 1.

The screw-driver in accordance with the invention is comprised of acylindrical shank 1 having an enlarged handle 2 at one end thereof, anda tool bit 3 at the opposite end thereof. The enlarged handle 2 may beformed of any material such as wood, plastic or the like, and ispreferably fluted in order to provide a secure grip for the hand H inengagement therewith, which serves to press the bit within the nick of ascrew S which is adapted to be rotated by the screw driver.

The shank 1 is provided with a gripping member for grasping by the thumband fingers of the other hand H. A limit stop 4 is affixed to the shankin order to transmit the pressing forces exerted by the hand H to thebit 3 of the tool. The gripping member 5 may assume the form of awing-nut provided with laterally disposed arms or wings 6, 6' on theopposite sides of a diametral bore which is reciprocably movable on thecylindrical shank of the screw-driver. A disc washer 7, integral withthe base of the wing-nut, abuts against the annular ring 4 whichprojects radially from the shank to provide the limit stop againstmovement of the gripping member, in the direction indicated by the arrowshown in FIG. I. The gripping member may assume any desiredconfiguration for engagement by the thumb and fingers, and may be moldedor cast of metal, plastic or any other suitable material.

- The screw-driver may be operated as a conventional screw-driver toengage the wedge-shaped bit 3 within the pick of a screw S to rotate thescrew in either an advancing or withdrawing direction. When increasedforce in the driving of the screw is desirable, the other hand is usedto engage the wings 6, 6' of the gripping member, in order to provideadditional force against the head of the screw to enhance the engagementof the bit 3 within the nick, so that the screw-driver may be turnedwhile the bit is securely within the nick. This secure engagementeliminates the shearing of the screwhead and improves the guidance ofthe screw as it is advanced by the screw-driver.

The limit stop 4 on the shank of the screw driver may be formed in manydifferent ways, such as by peening, or by soldering, welding or swaginga split annular ring within a peripheral recess or groove in the shankof the tool.

While the illustrated embodiment shows the gripping member reciprocablealong the shank of the tool, as indicated in the alternate positionthereof shown in dotted lines in FIG. 1, the gripping member may bemounted at a fixed position on the shank, between the handle and bit,for rotary movement relative thereto.

While the shank is shown of cylindrical contour, the same may bepolygonal or of any other cross-section as long as the gripping memberis capable of relative rotary movement thereon.

While the tool bit3 is shown of conventional wedgeshaped construction,the improved feature of the invention may be applied as well toscrew-drivers having bits of different contours for cooperation withcorresponding contours of screw-heads, such as the Phillips Screw, orhexagonal terminals or sockets.

I claim:

1. A screw-driver comprising a. an elongated substantially cylindricalshank having a handle at one end thereof for facilitating theapplication of rotary movement to said shank as well as pressure in theaxial direction of the latter, by one hand of the operator,

b. a bit at the opposite end of said shank for engaging the head of ascrew,

c. a protuberance extending radially from said shank adjacent to the endthereof remote from said handle and beyond said bit, and

d. a wing nut mounted on said shank between said protuberance and handlefor free rotary and reciprocating movement on said shank, with the wingmembers of said wing nut providing comfortable and balanced grip thereonbetween the thumb and finger of the other hand of the operator to exertadditional pressure in an axial direction against said protuberance toenhance the force of engagement between said screw-driver and screw.

1. A screw-driver comprising a. an elongated substantially cylindricalshank having a handle at one end thereof for facilitating theapplication of rotary movement to said shank as well as pressure in theaxial direction of the latter, by one hand of the operator, b. a bit atthe opposite end of said shank for engaging the head of a screw, c. aprotuberance extending radially from said shank adjacent to the endthereof remote from said handle and beyond said bit, and d. a wing nutmounted on said shank between said protuberance and handle for freerotary and reciprocating movement on said shank, with the wing membersof said wing nut providing comfortable and balanced grip thereon betweenthe thumb and finger of the other hand of the operator to exertadditional pressure in an axial direction against said protuberance toenhance the force of engagement between said screw-driver and screw.